Carbon-sulfur bond, hydrolysis

A one-pot synthesis of alkyl perfluoroalkyl ketones has been developed. Phosphoranes, generated in situ, are acylated with a perfluoroacyl anhydnde, and the resultmg phosphonium salts are hydrolyzed with alkali [4S (equation 48) Hydrolysis of a carbon-sulfur bond in 2-chloro-2,4,4-trifluoro-1,3-dithietane-S-trioxide, which can be obtained from 2,2,4,4-tetrachloro-l,3-dithietane by fluor-mation with antimony trifluoride followed by selective oxidations, opens the nng to produce 2-chloro-1,1,2-trifluorodimethyl sulfone [49] (equation 49)... 

Addition to thioamides.s Alkyl- or aryllithiums add to the carbon-sulfur bond of aromatic thioamides to give adducts that are hydrolyzed to unsymmetrical ketones. Reduction of the adducts with LiAlHj before hydrolysis provides a-alkylated amines. 

The carbon-sulfur bond of thiazines can be reductively cleaved (Sections 7.06.5.7 and 7.06.6.7) and 2//-thiazines, being imines, can be hydrolyzed (Section 7.06.5.5). Saturated thiazines (thiomorpholines) are stable toward alkaline hydrolysis <1981CPB1554> and Lewis-acidic boron trifluoride <1980JHC449>. 

C. Under these reaction conditions, a second carbon-sulfur bond was cleaved to lead to intermediate 123, which by reaction with a second electrophile at — 78 °C gave, after hydrolysis, the products 126 in 35-46% yield (Equation 14). Before the final hydrolysis, intermediates 124 (for R3R4CO) or 125 (for ClCC Et) may be involved in the process. 

Kaupp et al. employed ball-milling technique to transform thioureas 79 by reaction with phenacyl bromide to 2-amino-4-phenyl-thiazole-hydrobromides 80 in quantitative yields from stoichiometric mixtures of the reagents at room temperature (Scheme 4.21) [14]. In soUd-state conditions, base catalyst was not needed. The water formed in the reaction does not hydrolyze phenacyl bromide under applied mild conditions and was removed by heating at 80°C in vacuo. When the same reaction was performed in a melt at 110°C, partial hydrolysis occurred, which diminishes yield, while yields obtained in solntion were lower (80-90%). This Hantzsch thiazole synthesis starts with nucleophilic snbstitution on snlfur and formation of the carbon-sulfur bond (S-alkylation), followed by further reaction cascade which results in heterocychc ring. 

For several years, research conducted at California State University Fresno has focused on the utilization of carbon monoxide as an alternative to sulfur dioxide and other preservatives and sterilants as well (Muller et al., 1996). Carbon monoxide shares several of its chemical attributes with sulfur dioxide. Carbon monoxide has an electron deficiency on the carbon atom similar to the electron deficiency on sulfur in SOg. Additionally, the carbon has a pair of electrons available which can attack any Lewis acid and/or electrophile. Thus, CO can act very much like SOg and, in addition, has the properties of a strong electrophile. Further, once a covalent bond has been formed between carbon monoxide and one of its target molecules, it is usually a carbon-carbon bond which by its nature is nonpolar and thus difficult to hydrolyze. By comparison, carbon-sulfur bonds are polar and thus easily hydrolyzable. Compared with SO2, no carbon monoxide can be freed by hydrolysis (in either strong acid or base) from its... 

The broad class of products described as sulfonates results from reactions that create a carbon-sulfur bond and utilizes sulfur VI reagent SO3 and its derivatives and adducts such as sulfuric acid. A smaller number of sulfonate products are prepared using sulfur IV reagent SOj as well as its derivatives and adducts such as sodium bisulfite. The preparation of sulfate esters involves the creation of carbon-oxygen-sulfur bonds, and can utilize SO3, sulfuric acid, or chlorosul-fonic acid to form alcohol sulfates that are labile and susceptible to hydrolysis in the presence of water as well as elimination reactions at elevated temperatures, and must be handled under milder conditions than sulfonates during formation and neutralization. Numerous older reviews and recent publications exist covering sulfonation and sulfation processes to produce surfactant products. " ... 

Different alcohols and protected alcohols (as hemiacetals, silyl, methoxymethyl or phenyl ethers) were lithiated at the d-position to give the corresponding organolithium compounds. In the case of alcohols, a previous deprotonation of the hydroxyl functionality is required. The chiral intermediate 197 was prepared from the phenylsulfanyl derivative 196 first by deprotonation followed by carbon-sulfur bond cleavage with LiDTBB at low temperature. The reaction of the dianionic system 197 with y- and d-lactones in the presence of cerium(III) salts gave, after hydrolysis, spiroketal pheromones 198 (Scheme 2.27) [163]. 

Hydrogenolysis is analogous to hydrolysis and ammonolysis, which involve the cleavage of a bond induced by the action of water and ammonia, respectively. Chemical bonds that are broken by hydrogenolysis reactions include carbon—carbon, carbon—oxygen, carbon—sulfur, and carbon—nitrogen bonds. An example of hydrogenolysis is the hydrodealkylation of toluene to form benzene and methane ... 

Sultams like (190) undergo aminolysis with amines by nitrogen-sulfur bond cleavage (similar to hydrolysis), and suitably functionalised sultams (191) may also suffer carbon-nitrogen bond cleavage by a bimolecular (E2) elimination reaction (Scheme 79). 

Step 1 Make a new bond between a nucleophile and an electrophile and simultaneously break a bond to give stable molecules or ions. The reason for the extremely rapid hydrolysis of the sulfur mustards is neighboring group participation by sulfur in the ionization of the carbon-chlorine bond to form a cyclic sulfonium ion. This is the rate-determining step of the reaction although it is the slowest step, it is much faster than reaction of a typical primary chloroalkane with water. At this point, you should review halogenation of alkenes (Sections 6.3D and 6.3F) and compare the cyclic halonium ions formed there with the cyclic sulfonium ion formed here. 

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